Selective staking machine



y 28, 1953 c. R. CAMPBELL, JR 2,646,676

' SELECTIVE STAKING MACHINE 8 Sheets-Sheet l Filed March 20, 1951nvenlon Char/es 7?. Campbe/[Jr h/IS 470/147 July 28, 1953 c. R.CAMPBELL, JR

SELECTIVE snxmc momma:

Filed March 20, 1951 8 Sheets-Sheet 2 July 28, 1953 C. R. CAMPBELL, JRSELECTIVE STAKING MACHINE 8 Shegs-Sheet 3 Filed March 20 1951 fiwentor:Char/es 7f Cam obe/[Jr C. R. CAMPBELL, JR

SELECTIVE STAKI NG MACHINE July 28, 1953 8 Sheets-Sheet 4 Filed March20, 1951 y 28, 1953 c. R. CAMPBELL, JR 2,646,676

SELECTIVE STAKING MACHINE 8 Sheets-Sheet 5 Filed March 20, 1951zuaentor': Char/e: R. Canfbe/(JZ his (I y 1953 c. R. CAMPBELL, JR2,646,676

SELECTIVE STAKING MACHINE Filed March 20, 1951 8 Sheets-Sheet 6 Uni ' CfInventor:

y 8, 1953 CR. CAMPBELL, JR 2,646,676

SELECTIVE STAKING MACHINE Filed March 20, 1951 8 Sheets-Sheet 7 PatentedJuly 28, 1953 UNI TED STATES PAT ENT 0 FFl-CE SELECTIVE STAKING MACHINECharles R. Campbell, Jr., Beverly, Mass., assignor to United ShoeMachinery Corporation, Flemington,.N. J a corporation of.New JerseyApplicationMarch 20, 1951, Serial No.-216,636

8 Claims.

This invention "relates to machines 'for treatinghides and skins, andmore particularly to machines for staking leather selectively byutilizing :direct orfreely discharging cylindrical work rdlls havingcooperative but non-contacting blades. While the invention ishereinafter illus' traited as embodied in amachine .for performing fullwidth staking operations upon tanned hides and skins, it will beunderstood that in variou novel aspects it is not limited to use inmachines of ':the type herein illustrated.

The combination of special feed rolls with work rolls .having helicalribs :for Staking leather as disclosed herein is claimed in thecopendingapplication for Letters Patent of the United States Serial .No.283,736, filed .April 22, '1952, in the name aof :Charles :R. Campbell,Jr.

"The primary purpose of staking operations is tosoiten leather afterdrying by breaking up the cohesion between fibres and thereby generallyto improve its workability without detracting from its strength andappearance and without making itlimp and lacking intone. The procedureusually preferred 'for reducing the stiffness of a workpiece is that ofilexing'thehide orskin while it is being subjected to itension over astaking tool. The degree oftension createdahea'd of the staking tool inpresent full width machines is theoretically constant :and independentof the initial stiffness of the workpiece. dividual hide or skin to betreated'usually differs considerably :in the thickness and stiffness ofits several portions, .a more :rigorous "puiling and bending action is:highly desirable in certain of its portions and, :in fact, is requiredin order to obtain increased uniformity .of feel of the :leather. Inpresent commercial practice the degree of staking action applied toparticular portions "of any workpiece depends largely, if not entirely,on the discretion-of a-skilled operator who is simultaneouslyconcernedwithithe natureof'th'e work as well'as the'feeding andcontrolling of his machine. The operator or" a clamp staker,for-example, controls the staking tension as applied by .tool pressureover successive:narrow;paths-of about 6" in width. Hemust make numerousreciprocal strokes with the Working 'tool from a central portion to amargin and such sweeps, in view of the very irregularcontour of 2. hideor skin, overlap toconsiderable extent, especially in the centralportion. By using the means of selective staking as herein proposed, i.-e..-r.equiring a full Width staking machine automatically to :tensionthe several portions of each workpiece :in proportion to their initial:stifiness,

Since an inthe burden on an operator is relieved-and :a :high

rate of production of rather uniformly pliant hides and skins can beobtained.

A machine capable of selective staking zpreiertively light skin, andalso to treat the thickness and thinnest portions of a workpiece withap-,

propriate tension. Also, the tension exerted upon the sometimes weakermarginal portions of a workpiece as itis fed into .'0l'-'0l1t= Of thema-' chine must not be such as to effect either tearing .or creasing.Moreover, precaution is nor-' mally to be exercised that over-staking ofany portion be avoided .since. unlike under-staking, it cannot becorrected. Prior to the present invention, rolls with cooperativeinteracting blades have been tried for carrying'out the stakingoperation and such staking toolshavesimultaneous- 1y bent and pulledparts of a'workpiece but they have not produced a uniform feel orsoftness in all parts of a hide or skin, :their failure seemingly beingattributable'to their inability to produce flexures under differenttensions thatawere nice- 1y controlled by the initial localizedstiffness 'in the work portions themselves.

.It is therefore a general object of this invention to provide animproved full width leather treating machine which shall be capable ofselectivel staking hides .or skins. Another object of the invention isto provide :an improved staking machine of the rotary blade 'type whichshall be relatively simple in construction yet be capable of a highoutput 'of hides or skins havingauniform .ieel.

Pursuant to these objects and in accordance with one feature, theinvention comprises in-combination a pair of cooperative work rolls bothhaving large circumferences provided respectively with rigid :bladesarranged in groups spaced apart :circumferentially of each roll theworkengaging ends of the blades of one roll 'being sharp and those ofthe other being relatively blunt or rounded and together affording sucha large nurriberoi directional'reversalsand depth of non-contactinginterengagements as to provide the work with a long, tortuous treatmentpassage therebe'tween, and feed rolls adjacent to the ibite of saidworkrolls on their charge side and rotatable at a lower peripheral speedprogressively to spread the workas'it is tens'ioned'by the coaotion ofsaid work rolls.

Still another feature of the invention is the combination of a pair ofcooperatively related staking .rolls having grouped interacting bladesarranged helically, said blades being in units of three or more groupedthroughout their length and, adjacent to their bite on the feeding side,feed controllin means comprising a pair of feedretarding rolls, andmeans for driving both sets of rolls at unequal peripheral speeds.

These and other important features of the invention and novelcombinations of parts will now be described in detail, reference beinghad to the accompanying drawings in which:

Fig. 1 is a front elevation (as viewed by an operator) of the left sideof a non-through feed staking machine, a portion of the machine beingbroken away to reveal construction detail;

Fig. 2 is a front elevation of the right side of the machine partlyshown in Fig. 1, a portion being broken away, and showing the lower workroll raised to its operatin position;

Fig. 3 is a left end elevation of the machine, portions being brokenaway the better to reveal construction details;

Fig. 4 is a vertical section taken on the line IV--IV of Fig. 1 andshowing the staking rolls separated;

Fig. 5 is a section taken on the line V-V of Fig.

Fig. 6 is a section taken on the line VI-VI of Fig. 3;

Fig. 7 is a vertical section looking to the right as the machine is seenin Fig. 2, and showin the rolls in their operating positions on aworkpiece;

Fig. 8 is a perspective of helically bladed work rolls embodyingfeatures of the present invention;

Fig. 9 is an enlarged and somewhat diagrammatic section takentransversely of operating portions of the straight or helically bladedwork rolls and illustrating the tortuous path of a portion of theworkpiece;

Fig. 9a is a view similar to Fig. 9 restricted to grouped helicalblades;

Fig. 10 is a front elevation on a reduced scale of hydraulic mechanismfor movin the lower work roll into or out of operating position;

Fig. 11 is a perspective schematic view of a workpiece being staked;

Figs. 12 to 15 inclusive are front elevational views of the operatingblades of a pair of helically bladed work rolls, on a reduced scale, andin progressive operating positions through 180 degrees of a cycle; and

Fig. 16 is a schematic view of group blades cooperatively building uptension on a workpiece portion passing through a treatment zone, thefiexure angle for both sharp and round blades here being equal.

The staking machine herein disclosed is illus trated and described asprovided with different pairs of Work treating rolls each of which isconstructed and arranged to stake leather selectively. As seen in Figs.1 and 2 the machine is shown as provided with work treating memberscomprising a pair of rotary cooperative rolls 20, 22 (both preferablybeing of larger diameter than heretofore used, i. e. about 10-12 inchesor more in O. D., to afford a large area of chordal mesh) provided withspaced straight blades 24, 26, respectively, extending lengthwisethereof and having a generally L-shaped cross section. The bases of theblades may be welded or otherwise affixed to the rolls or, if desired,the blades may be machined on the rolls or even caulked therein. Incontrast to some types of staking rolls the blades 24, do not touch butare positioned to interengage without contact when the rolls 2B, 22 arein operative position. This is to say that the respective working bladesof one roll are positioned to be disposed centrally in the spacesbetween adjacent blades on the other roll. As best seen in Fig. 3 theblades 24 of the roll 20 have well-rounded or cylindrical-shapedworkengageable ends 28 and are adapted to engage the grain side ofleather. One form of construction for rounding these ends or edges 26 isto fabricate sheet brass, a radius of inch being successful, forexample, in avoiding grain boarding. The blades 26 of the lower roll 22are adapted to engage the flesh side of a workpiece and are preferablyquite pointed and spaced relatively to the edges 28 to provide amultiple bending involving sharp directional reversals of a workpiece.The number of blades provided on each work roll is determined by theminimum number of directional reversals or fiexures required to build upworkpiece tension adequate for staking the heaviest skins, ashereinafter described. Trial has indicated that with work rolls of theproposed large diameter, about 24 to 32 blades per roll when spacedcompletely about a circumference-and with corresponding intervals.

(less than 1 but more than if not occupying an entire perimeterarepreferred. Also a desirable number of passes of a blade tip per point ona workpiece surface has been found to be about four or five.

As seen in Figs. 1 and 2 the roll 29 has its shaft 30 mounted inbearings 32 carried at each end of the roll 20, said bearings beingfixedly mounted on the frame 36 of the machine. The lower work treatinroll 22 has its shaft 38 mounted at each end in bearing blocks QBrespectively secured-to the opposite and upper ends of a swingablemember e2 that is pivotally supported by a stud 44 (Fig. 2) threaded inthe frame 35 and a stubshaft 45 (Figs; 1 and 3) having hearings in theframe and a bracket 41. Hydraulic mechanism subsequently to be explainedis pivotally connected to a central dependent arm 46 of the member 42and is effective to raise or lower the roll 22 with its blades 23relative'to the roll 28.

For the purpose of conveniently and properly feeding a workpiece W (Fig.7) to the bite of the rolls 28 and 22 there is provided a pair ofcylindrical rolls 50 and 52 and an inclined worktable 54. machine frame36 and is adapted to conduct a full width hide or skin to the bite ofthe rolls 50, 52 which are preferably covered with a resilient rubber orrubber composition. These feed rolls are alike in construction, theirrubber surfaces having the same number of thick, flattopped ribs orlands 5% extending helically and with opposite lead from pointssubstantially midway of the length of the rolls. The ribs 55 on one halfof a roll are preferably staggered from those on the other half to avoidcreasing or bunching the work. It should be noted (Fig. 7) that the ribs55 of each roll do not mesh with those of the other, but are arranged inphase and rotated so that their peripheral surfaces cooperate ingripping opposite sides of successive segments of the workpiece W. Therolls 50, '52 are respectively affixed to shafts 58, and driven by meansto be described at a peripheral speed less than that of the work rolls2t, 22.

Advantageously, the mounting of the shafts 58, 60 is such as to permiteasy adjustment of the pressure exerted by the rolls 50, 52 on the workpiece W and they are automatically separableafter lowering of the workroll 22 as will herein- The latter is secured to the front of theace-agave after beenseern end of the shaft. 581 is'v providefi with a-bearing journaled in one end". of a; gearplate fii (Figs; 1; B andi l):pivotally-mounted: at its-Qther' end orr astub shaft 63% journaled; inthe machineframez. Theother endofthe' shaft: 58 is journaled in& an arm.65 (Fig. 7.)= fulcrumed onastub: shafted: The: platefifi' is adjustableasitd its upper limits; or pivotal movement suite ably: to: maintain;operating. pressure of? the:- roll th omdifferent types of worle lilorthatspurpose a: vertical arcuate slot 6 a: in; the frame: 36, best seemin Fig; 7;. slidably accommodates a; stop block. 68%. engageable with:the; bottom: of; arr. adjusting bolt: 'lfl'threazded: in the frame. Theblock so bolted to the plate 62;, The: shaft has endibearingsirrthezcorrespondingarms of'apair' Of. bella cranks T 2:pivotally secured: to the; frame 351 by atie rod. li t (Figs. 1; and:2'). Each. lower. end. of the other arms. of: the: bell cranks; 1-12.pivotallycarries. a trunnion, block 15: having: a bore to; receive athreaded eye bolt. M31 connected to: the member-42 The respectiveeye-bolts l6 adinstably carrythreaded stop collars 1.8 and 8-0, thelatter bearing ona spring 82: abutting. the block 1.4.

Power for driving. the work and feedv rolls 2t, F2; and EU; 52-,respectively, in fixed speed ratiois-providedibyanelect-ric motor.(Figs. 1 and-3') bolted: to the frame 36 and having an armature shaft82. sprockets: 94 and 96 respectively having chain driving: connections9.3; with sprockets 9'1, 99' mounted on a commonstubshaft 93 journaled:in.- the frame; 35.. As. best seen in Fig. 6 thesprocket 91 is freelyrotatable on theshaft 9-8 and: the. sprocket 99 iskeyed thereto. Means(Figs. 3 and 4) for driving the feed rolls 5U; 52 comprise achain.tellhaving" operative connection; with: the: sprocket 91- and a largesprocket N12,. therlarger sprocket H12"beingfixedly'mounted on. one.end. of a short shaft Elitwhich' carries inboard a. relatively smalldrive gear I06. Thelatter drives. meshed gears. tilt, Hi), H2. and l=l4-supportediby. thegear plate 62, the gear I I 4; being. mounted. on.thefeed. rollshaft 58.. Also drivenby. the gear Hi6. are meshed-gearsH6, H8; 1.2.2, and. I24 (Figs; 3 anda l rotatabl-y supported by anarmofthe. bellcrank 12, the gear L24 being mounted. onthe. feedv rollshaft,66..

The. means for driving the work rolls 2 9,, 22.- comprisean endlesschain Hit. in. meshwiththe sprocket. 9.1. on. the stub shaft 98 and:meshing with. a. sprocket i313 rotatably mounted. on an"; axle I36;-(-Fig s..3; and: 4:) havingbearings in the frame; 36 at the rear. of themachine. Eor'the: HUIPQSB? of. taking, up; or slacking ofi}. on the:chain- I; if need be,.the axle; i3 3: has-an eccentric portionengageable with a binder post #38 (Fig.2 threaded into the" frame:endless chain 3ft meshes with a sprocket IE9 rotatableon the stubshaft45; with a sprocket M2 keyed to-the shaft and then returnsto' thesprocket 91. A sprocket PM on the stubshafl? E5 drives: an endlesschain- M6 meshing" with a sprocket wheel M8 keyed to the work rollshaft3-8.

In Fig. 3'it willlbe noted the sprocketlwheel M3 is. provided; with fourarcuat'e and. concentric slots I50, eachreceiving a bolt I52 threadedinto. the. shaftSBl. By adjusting, these. bolts. suitably in theslots55:3. thewheel M8 maybe adiustably afiixed. relatively to. the roll- 22.to position. the blades- Zfz intermediate the worlclng blade ends-z2 8-.Amiddlepositionis: usually desired. for each blade 25; with. respect taadjacent: blades! 2-8; the ad.

Fixedly mounted onthe shaft 92- are i instability being preferred; to;accommodate de flecti'on and: play in the. drivemechanism.

Coming'now'to Figs..2,' 7 and. 10;. attentionxis. invited to thewhydraulic:- control means provided.=. for. raising or. lowering: the:work'roll. 22' relative: to theroll- 20. An electric motor- 1560' isbolted to thertop of a tank I62 containing'fluid and is.coupledtotahydrauliopump IE4. A trea'd'le,- H36 when depressed,actuat'es valves a' housing:

v in conventionalmanner to require fluidr front the tank. I 62; to bepumped via piping I61: into one: end of a horizontal cylinder 168:secured to: the frame. Piping I68 connects the valve housing lfi iiiwiththe other end of the cylinder N38 The fluid under. pressure in thecylinder. is applied to'a piston therein (not. shown) which is moved. to'the left, as viewed in Fig; 10, to displace a: piston rodv 179:connected to the depending arm: 46;. Accordingly, as best: seen inFig.7, operation. ofv the motor Hill and pump. MM is effective. toswingthe member 42 on the stud: 4t: and stube shaft 55 to raise the roll22. into" operating posttion, the-upperv limit: of movement and exactlydesired operating position being. adjustably: do!

, terminedi bya stop stud' H2 threaded through: as

lug securedtothefrarne 36:, an end of the stud Hzbeing engageablewiththe arm 46.

When the. above-mentioned straight bladed rolls 23, 22 are employed itis found? thatsatis= .factory results are obtained on: those leatherscapable of withstanding. the stressesv developed in theirportionstextending between the feed'sandwork rolls, but. that other:leathers may. become: torn as'a. consequence of stress concentrations atan: edge point along. a. very irregular margin,

If full; widtl r staking, i. e., staking. right out to the marginsof aworkpiece, is: required without regard" for such: as at: out turnedishanks.

therislcof: rippingstraight bladed rolls perform effectively, theiroperation and selectivity being similar'to. that; of: the group-bladedrolls 18 it; H32 about. to: be discussed:

Inorder to avoid any danger of damaging a workpiece as by tearing, thepresent invention provides: improved? work. treating members comprising.a pair of helically: bladed rolls 58-9, 82 best seen. inLFig; 8. Theupper roll I' SEI- has its blade ends rounded cylindrically as describedwith regardto' the blade ends of-the-roll' 23; and

I82 is provided with blades having the roll sharper ends: or edges. Therolls- I89; 182 are notlfullybladed for reasonsto be explained; buteaelrcomprisesaright and left hand blade groups helicaliy arranged. Asviewed in Fig. 8 the left hand: groups of the roll Hit are designatedI84, 1 and; its: right. hand groups are designated P88; I 91}:the'left-hand groups-of the roll- !Sl. are designated. 1 .92;. I29 and;its right-hand groups are designated? b96 I198. The upper or grainblades cooperate by: interengagement; but not contact,

with; the lower: or. flesh blades and', preferably; thoughnotnecessarily-the rightand left halves ofboth. rollsrec; 182i include,respectively, only twos groupsiofb lades. The two groups of bladesonzthe right: halves of both: rolls I86, E82 extendfrom': a medianposition longitudinally of the rolls and witluequalbut opposite leadwith ref-'- ercnoeto the twogroupsonthe leithalves. The roll,diameters;. helix angle, and the number of blades. in. each group arepreferably so related that, in each work roll; a maximum of only oneleft-hand and one. right-hand group I contact the workpiece: one time:as-will be later explained with: reference: to: Figs. 12. through. 15;In this connection. it; should beanotedithat the blades are:-

grouped throughout their length and those of one group unit do notoverlap those of another. It is found that three or four blades to agroup are sufficient to produce high-quality staking on a wide varietyof leathers. The further characteristic to be noted as to these helicalrolls is that the right and left-hand blade groups are alternatelyspaced about the periphery at the midpoint longitudinally of the rolls,thereby avoiding creasin of the work which may otherwise occur centrallywhen fully bladed helical rolls are employed.

In the above description it has been assumed that the workpiece W wasmoving during treatment from the feed rolls 50, 52 and then through thebite of the work rolls 2D, 22 or I89, 182 in the direction of theirrotational effect, such practice being termed infeed, as indicated inFig. 9. When a workpiece W is moved during treatment in an oppositedirection, 1. e., counter to the rotational movement of the work rolls,the practice is termed outfeed. Ordinarily a decreased depth ofinterengagement of the blades is required when the outfeed system isused. The illustrative machines are capable of infeed or outfeedoperation, the more common infeed system simply requiring an operator toreverse a workpiece W end-for-end after a first portion has been staked.

In the usual infeed operation of the machines the feed roll 50 rotatesin the same direction but at lower peripheral velocity than the workrolls 20 or I80, while roll '52 rotates in the same direction but atlower peripheral velocity than the work rolls 22 or H32. After passingthe workpiece over the worktable 54 grain side up, the feed and workrolls having been closed for cooperative action by depression of thetreadle I65, the coacting ribs 56 of the feed rolls grip successivesegments of the leather and direct it to the bite of the work rolls wellspread-out, any bagginess in stock between the helical ribs 56 seeminglybeing carried to the side margins of the work. By reason of the greaterperipheral speed of the work rolls, the feed rolls 50, 52 also act as adrag or retarding means controlling the rate of feed, the work beingsubjected to the tension generated by the staking rolls as theirrespective blades operate frictionally on the grain and flesh sides.

Such improved rolls stake a larger variety of leathers safely even whenthe latter are of irregular configuration, the blade groups localizingthe zones of treatment so as to reduce the total pull force between thefeed and work rolls. It appears that blades more nearly parallel withthe axis of the work rolls produce a greater tendency toward edgeripping and toward staking near the edges. Accordingly, employing agreater helical blade angle advantageously introduces less tension alongworkpiece margins where there is, in certain leathers, little initialstiffness and little or no staking is required. Moreover trailing bladesof interacting blade groups accomplish maximum staking. Since sharperflesh blades produce better feeling leather, a further advantage isderived from grouping the blades as above described in that a trailingflesh blade edge, as at X in Fig. 9a, can be made sharper than isfeasible on fully bladed cylinders; similarly more advance flesh bladeedges of a group, as at E, or E and D, in Fig. 9a, can be made very dullto produce a tension at X which is properly more a function of stiifnessin the leather than of friction generated as a result of roughness ofits flesh side.

The tortuous path of the workpiece W as seen,

in Figs. 9 and 9a, for example, affords a basis for a probableexplanation of the selective action accomplished by the straight orhelically bladed machines employing the unusually large diametered workrolls. It may be considered with regard to Fig. 9 that at any givenmoment tensionin the workpiece W, and therefore a corresponding stakingeifect, will be built up as a result of the blade friction developed atthe points A, B,

C, D, and E and the pull required to flex the leather at these samepoints. Staking at point E has about been completed but has justcommenced at point A. In the work segment leaving point E. there islittle or no tension; proceeding counter to the direction of feed,tensions between E and D, D and C, C and B, and B and A, arepoint A thanis the situation with initially softer leather. This is to say thatforces acting to flex initially stiffer leather at the points of bladecontact with the work increase the staking tension at A far more thanthe lesser forces utilized in flexing less stifi leather. The stiiferportions of a workpiece therefore automatically require the machine tostake them more rigorously, the degree of staking in a locality beingcommensurate with the initial stiffness of the workpiece in thatlocality.

With respect to Fig. 9a, when within the work treating zonecorresponding to a chordal intercept denoted by the distance Y-Z, theduller advance flesh blade edges E and D build up tension in theworkpiece for operation by the sharp trailing blade X. The latter alsocreates added tension of its own. If harder, stiffer leather is fed pastblade X greater resistance to flexing at E and D creates extra tensionback at X to increase the staking effect. Thus the advance blades have atension hunting tendency capable of automatically selecting stakingtension com mensurate with the degree of initial stiffness. It isimportant to note that the extent of the chordal intercept Y-Z and thedepth of intermeshing of the blades may be accurately controlled asappropriate to the work by adjusting the stop stud I12. Tension decreasein the treatment zone, considered in the direction of feed, is moremarked when the intercept Y-Z is longer and heavier workpieces may thenbe treated.

It is also advantageous to analyze from a mathematical viewpoint themanner of selectively staking leather. Reference being had to Fig. 16,by further examining the hunting action of successive group blades inbuilding up tension by frictional engagement with workpiece segmentswithin the treatment zone, and as consecutively spaced from the point ofdischarge, it may be shown that the tension built up is commensuratewith the stiffness of that portion of the work being discharged. Let itbe assumed that the workpiece is not undergoing acceleration ordeceleration, that the angle of leather flexure at a blade 280 is 0, andthat T1 represents the tension in that portion of the leather notconstrained but just being discharged. Tension T1 (relatively small) iscaused by inertia,

weight and stiffness' Then,

ses m -.=.of-:that.portion ibeingzdischarged but which :is-just acoininginto contact withithe advance blade.

.q-advance blade Zllfizand being left behindaby it. 'It

:will be recognized that though the workpiece is being fed from right toleft asiviewed injFig. .16,

:the segment aotedonby Tzmay be considered to he moving from left to.right relatively .to :the "blade 2%. The resolvediriction .force may.be :designated N :where its the coefficient-bf I friction ofithebladecontacting leather and Tz cos.6 =T1 cos +Nf ssubstituting for N in thisequation and solving,

lei-f tan 0) 1"'f'tan e- The coefficient of friction, f 9I1- S:11a.1p"bli.deS ma ea ms t .5 1 t gqqe fic 5f "time 1 W s r ue ed lade .23ma be assumed to be 0.3. in these conditions wheno is 30 de r es =3 a d3-? a es f to girl emultiplier for each sharp blade. After the :nextdirectional reversal of-the work ;1'+f (r tan 0 i a sumi th seine fissuangle, and h e e 1T3 =3 .72 T1 X11242 =5.30T1 multiplier for each ndblade is 1.42.

From the above it will be seen that the tension .buildupinterms of T1stifiness -increasesrapidly. jQ'perjatijng tension to within50'7;5% of:the rupti'ire strength of "a workpiece is developed selecely by "this"metrics; the 'maximum tension I usually being limited 'to this range byrestricting the number of cooperating-blades andapproprilines shown*onthe workpiece indicate the alternate bands of staking ;acc oniplishedby theblade y groups. 'I he width of:a:-b.andzmay be cdn'sidered torepresent the approximate extentiof feeding of= -the work v in the time5 interval between succes- 10 :in rigs. 12 :through 15 the gathering ofstock in the zto'rtuous ,path causes a tautness extending xdiagonally inthe workpiece back .topitsedges'adjacent to the feed {roll bite, :asindicated in Fig.

. 1-1 :by linesgp, .q for the stock gathering'on the leftfloalioiatheroll I 82 and-lin'esr, s .for the stock gathering on the right halfthereof.

The 'major .portion of staking tension, as effected for example from the.point 'A :(Fig. .9) ,or along possible loci 1a .or a, -.is about:normalto the biteaoi the fee'd'rolls 58, 52. The diagonal taut- =ness referred.to above is along the lines fiat- Zter,'i. 2e. more nearly parallel tothe axes of the work rolls, when the gathering of stock in .the tortuouspathis disposed centrally .(Figs. 12,-14) :of those rolls, andshould notbe flatter thanLthe helixangle of theiblades 26, '28. The reason *forzthisis that, if thezgeneral lines of tautness :be efiatter gth'an' the:blade :a'n'gle, :the tension eresultaing-inltlie work cis .1101]dependent upon the degree or :leather stiffness and decreases toorapidly as the loci .of work contacts approach the side mar- .giIlS. Asregards-agiven work blade helix angle and the length of work rolls thereaccordingly-is 2a limiting relationship to be recognizedin the:distance'the bite of the feed rolls 59,52 is-spaced from the bite ofthe vwork rolls, such distance being denoted. by D in-Fig'l-ll.

The illustrative machines, .not being of the through feed type, requireai'eversal endefor-end .in feeding the work after .a, first leadin'portion @has been staked. The hydraulic means (Fig. 10) "under thecontrdliiof the operator rea'dilyenables him to free a lpartially stakedworkpiece {in \the Jrna'chine .by first dissociating the work irolls2:2Iand then the feed rolls5flf 52, as will now be explained. It isofcourse important that the latter rolls continue to serve as workretarders until .after the continuously rotating work fblad'es 26, '28cease to exert a tension on the workpiece. Assuming the roll 22 to 'havebeen raised into operating position, as shown in Fig. '7, by the :mot-or190 and the pump I8 5, as previously described and that it is now"desired to withdraw the workpiece, the -operator allows the depresseditreadle H56 to be'raised (as by spring means not shown). This returnmovement of the 'treadle 1'66 is effective to shift the control valvesdeiferred to above but not shown) so-that pressure .in the l'pipi'ng 161is relieved and, under the?ihfluence of gravity upon the lower work andfeed irolls, the member 42 isswung counter-clockwise (as seen in 7)about the stud M and stubs 7-) and against the resistance afford-ed' bycomsive blade group passes and is only about of the total length(measured in the direction of feed) of the work undergoing treatment inthe tortuous path formed between the work rolls. Approximately theremainin of such length is staked during the preceding and the followingoverlapping blade group passes. The loci of work contacts of flesh bladeends, as at A, C and E of Fig. 9, are illustrated in Fig. 11 asdeveloped in the form of corresponding lines a, c and e, or a, c and e.As noted in Figs. 12 and 14 the right and left helices of blade groupsmay operate together on the width of a workpiece and the diverging pathsof contact act to pull taut the intervening work. In any of thesituations depicted pression of th'e springs 132. The feed roll 52 "isthereb'y yieldingly dissociated from the roll 50 and "the workpiece maythen'be malhually rieivrnioved from 'the machineft'he *sepa'ratioh ofthe recurring occurring subsequent -'to the dissociation of the workrolls by reason of the adjustable idle movement of the collars '58before engaging the blocks 15. It will be apparent that on commencingthe next staking operation by depression of the treadle I86, the springs82 are effective upon compressive movement of the stop collar to returnthe feed r011 52 to its yieldable operating position as the member 42 isagain swung clockwise to carry the collars 18 away from the blocks l5.It should be noted that the roll 52 is thus returned to feeding positionbefore the work roll 22 or I82 is returned to operative 11 position. Thecollars 80 are threaded on the eye bolts 16 to provide a means foradjusting the pressure exerted by the feed roll 52 on differentthicknesses and types of leather.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

1. A selective staking machine comprising a pair of feed rolls, a pairof work rolls cooperatively rotatable to operate on opposite sides of aworkpiece progressively as it is received from said feed rolls, each ofthe work rolls having three or more blades grouped throughout theirlength, peripherally spaced, and extending lengthwise thereof, thework-engaging edges of the blade groups on one roll respectively beingintermeshed and disposed centrally of adjacent work-engaging edges ofthe blades on the other roll, the

spaces between said blade groups being greater than the spaces betweenindividual blades, and means for driving said work rolls at a greaterperipheral speed than the feed rolls to tension the stock between saidpairs of rolls by forces cumulative between the working blades.

2. A machine as set forth in claim 1 further characterized in that theblades on both Work rolls are arranged helically in spaced groups andextend with equal but opposite lead from a position substantiallyintermediate the length of .their respective rolls.

3. A machine as set forth in claim 2 further characterized in that thespaced groups of helical blades are staggered peripherally at the saidintermediate position to avoid creasing and bunching of the workpieceduring treatment, and no portion of a blade group is in overlappingrelation to another lengthwise.

4. A machine as set forth in claim 3 further characterized in that theblades in each group are limited to not less than three, and the groupson a roll are diametrically disposed but do not overlap lengthwisethereof.

, grouped throughout their length and all groups being disposed innon-overlapping relation, and means for rotating the work rolls to flexand ten- I sion against said retarding means the stock of the workpiecegathered in the tortuous work passage between interacting blade groups.

6. In a machine for selectively treating hides and skins or the like apair of cooperative work rolls each having one or more units of at leastthree similar helical blades arranged in peripherally spaced groups onboth sides of an intermediate point in its length, the lead of a groupon one side being equal and opposite to that of a group on the otherside, all of said blade units being grouped throughout their length, thegroup blades on one work roll having blunt work engaging ends and groupblades on the other work roll having relatively acute work-engagingedges respectively positioned to interengage centrally the adjacentblunt ends, mechanism for moving one work roll toward or from the otherto adjust the frictional drag and bending effected on a workpiece by aseries of said interengaging blades, and feed control means forresisting said drag.

7. A machine as set forth in claim 6 further characterized in that thework-engaging edge of the trailing blade of a work roll blade grouphaving the relatively acute work-engaging edges is sharper than thework-engaging end of the advance blade of that group.

8. A machine for selectively staking hides and skins comprising rollsfor feeding a spread-out workpiece at a predetermined rate through atreatment zone, a pair of work rolls in said zone adjacent to saidfeeding rolls and having interacting helical blades for acting upon saidworkpiece as it is fed, the blades being in groups spacedapart'circumferentially of each roll and throughout their lengths, andthe blades at one end of each work roll being opposite in lead to thoseat the other end of that roll, and means for rotating the work rolls tocause the blades frictionally to engage the work and to tension thatportion of the work which is between the feeding rolls and the workrolls.

CHARLES-R. CAMPBELL, JR.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 389,511 Hofiman Sept. 11, 1888 528,638 Lawrence Nov. 6, 1894587,717 Evans 1- Aug. 10, 1897 592,952 Evans Nov. 2, 1897' 975,628McKeen Nov. 15, 1910 1,016,279 Lougee Feb. 6, 1912 1,036,335 Quirin Aug.20, 1912 1,070,731 Quirin Aug. 19, 1913 1,173,155 Whitney Feb. 22, 19161,204,914 Wayland Nov. 14, 1916 1,821,094 Harding Sept. 1, 19312,175,570 Pierson Oct. 10, 1939 2,366,242 Edgar Jan. 2, 1945 FOREIGNPATENTS Number Country Date 1,961 Great Britain of 1871 163,384 GreatBritain May 2, 1921 227,916 Great Britain Jan. 26, 1925

